Think about the last time you brought a new car home. Did you buy or lease it? What went through your mind when making the decision? The right answer depends on your individual perspective and situation, whether it's practical factors such as monthly payments or psychological factors like style and appearance.
Similar thinking needs to be applied to today's hiring strategy. Most industries have a long-standing inclination to "buy," i.e. hire employees who tend to stick around for a long time. You can find plenty of examples especially in capital intensive and network model industries. Others have grown to operate more on a "lease" mentality, most notably agencies and professional services.
During the interview process, many managers vet candidates as if they're being hiring into a tenure track. Consequently, candidates must play the game and feign that they'd never dream of leaving if hired. This generates a lot of wasted energy during the recruiting and ramp-up processes on both ends.
The way people think about work has remained fairly static for most of the 20th century and into the next. Sociologists say that the concept of work/life balance comes from a world where separation was necessary; work was a dull, necessary evil to support goals that society established for a "normal" lifestyle. Today's workers want to merge their passions and profession. We should choose where we work with an "opt-in" mentality and opt-out just as easily. Isn't that what at-will employment means? But what company is ready to foster this type of open culture?
Leverage isn't a bad thing - it can be bad when improperly applied. Likewise, not using leverage limits opportunities. Managers must orchestrate a balance in employees leased vs. "owned." Employees must recognize their inclination for short- vs. long-term affiliations and seek positions accordingly. You might be able to fool others, but ultimately you'll end up fooling yourself unless you recognize your inclination.